Gravity The force not the movie. Forces Force (N) is any influence that can change the trajectory,...
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Transcript of Gravity The force not the movie. Forces Force (N) is any influence that can change the trajectory,...
Gravity
The force not the movie
Forces• Force (N) is any influence that can change the
trajectory, speed or shape of a body.• Change in state of motion of a body• Distortion of a body
Forces
• A force is represented by a vector with both direction and magnitude
Forces applied…
• In the same direction as motion will cause an acceleration.
• In opposing direction to the motion will cause a decceleration of the object
• In perpendicular manner to the motion will cause a deviation of the object.
Forces
• If a force is applied– in the same direction as the motion of a body it
will accelerate
– in the opposite direction as the motion of a body it will decelerate
– Perpendicularly to the direction of motion of a body it will change trajectories
Forces
• An equilibrium of forces is achieved when the resulting force is equal to 0
• ***– Add forces in the same direction– Subtract forces in opposing direction
1. Weight vs. Mass
Definitions
MASS: measure of the quantity of matter in an object
WEIGHT: measure of the gravitational force acting on an object
Mass• Amount of matter an object has
• Measured in g or in kg
• Is measured by a balance
Weight• Pull that gravity exerts on
an object
• Measured in N
• Measured by a scale
• If the mass increases…
To recap:
• Mass and Weight are not the same
• Mass is the amount of matter• Weight is the gravitational pull on this matter
• Mass is measured in g or kg• Weight (being a force) is measured in N
• Mass and weight are proportional to one another
2. Calculating the gravitational Force
Fg = mg
Calculating the gravitational force
• Fg = mg– Where Fg = gravitational force or weight (N)
m = mass (kg)g = gravitational constant
• If an object has a mass of 30g what is its weight in Newtons on our planet?
• What if it was on Mars?
Astronomical Phenomenon
• Tides:– Gravitational effect of
the moon (and Sun) on the hydrosphere
Astronomical Phenomenon